Process of treating wood-pulp and the like



Patented Mar.1,19,38

PATENT OFFICE V 2,110,032 raooess or maa'rmo WOOD-PULP AND THE LIKEHarrison R. Williams, New York, my, assignor to International PaperCompany, N. Y., a corporation'of New York Application May 24, 1926,Serial No Drawing.

New York,

No. 111,389. Renewed July 22, 1931 I 12 Claims.

My invention pertains to anovel and beneficial method of treatingwood-pulp or equivalent ma- 1 terlal to produce therefrom a light,porous, absorbent product resembling cotton and capable of replacing thelatter in many of its common uses,-

a portion of the steps of the process resulting in a somewhat differentbut desirable sheet product which may be satisfactorily used in variousways.

.Amain purpose of the invention is to supply a l0 process of this typewhich is rapid in its production of the desired results and which can beperformed economically and efflciently and without objectionable,dangerous ,or otherwise unsatisfactory features.

lo In the preferred manner of carrying out the new and improved process,the wood-pulp, after having been disintegrated in water, is renderedporous and full of gas pockets or cavities,-which remain in the producteven after the latter is dried, and thereafter the material may becarded to render it more fiufiy and porous, whereupon it closelyresembles cotton in appearance and texture and is very highly absorbent,although it may be rendered more or less moisture-repellent if required.7

I will now proceed to describe in detail the preferred way of practicingthe new process, but it is to be borne in mind that this is by way ofexample only, and is not to be taken in a restricted sense,

because many changes or modifications may be incorporated in theprocedure without departure from the substance-or essence of theinvention as defined by the appended claims, and without the sacrificeof any of itsmaterial benefits and advantages. v a

v A suitable quantity of ordinary, dried, or only partially dried,wood-pulp is thoroughly disintegrated or finely divided in water in anyapproved manner, as by the use of heaters in a receptacle or othermeans, after which the surplus water is drained from the stock in astorage tank.

,When the solution has been brought to a point where the amount ofdisintegrated stock equals approximately five (5%) per cent. by weightof 5 the. water, for eachgallon of the liquid one (1) gram is added of asolution containing one thousand (1000) cubic centimeters of rape-seedoil, one (1) gram of crystallized phenol (CsHsOH) and one gram ofglycerin (CsH5(OH)3), and a mechanical agitator within the vatcontaining the materialcauses the pulp to be thoroughly subjected to thesolution. V

The contents of this vat are now slowly drawn off into the wet end ortank of a sheeting machine, and as the liquid flows into such tank, for

(C1,: ISL-2) each gallon thereof, one 1) gram of bicarbonate of sodium(NaHCOa) and one-half (V gram of potassium-hydrogen tartrate (HKC4H4Ou)or socalled potassium-acid tartrate (KHC4H40s) is added. The material isthen dried in continuous sheet form without subjecting it to theactionof pressure rollers, the water being extracted partly by drainage,partly by suction, and partly by heated air, or in any other approvedmanner, and as the u bicarbonate of sodium gives up carbon dioxide byreason of the action of the potassium-hydrogen tartrate. thereon,innumerable pockets or gas cells are formed, which render the materialsoft, porous, and of a very open nature, in which form 1 it can beeasily carded.

This pulp in drying does not assume the hard, solid or denseconditionwhich ordinary woodpulp takes when dried, but, owing to the gasrecesses and spaces, it is porous, elastic and relatively soft andflexible, and retains the fibers of the initial pulp in more or lessmiscellaneous interlocking relation.

The glycerin has a tendency to soften the pulpfiber and to leave thematerial with an added degree of elasticity or resiliency, orflexibility, which aids or facilitates the subsequent carding operation.

Such sheet of material is suitable for use in many relations, butjinorder to produce the final product therefrom, it is desirably sprayed onone surfacewith a suitable deodorant, such as formoclor, or any otherappropriate deodorizing agent, preferably, but not necessarily, oneincorporating chlorine.

This deodorant thus applied to the absorbent sheet of material quicklyimpregnates the same, so that during the subsequent carding operation itis thoroughly dispersedor distributed throughout the whole material, andin addition its slight moisture aids the carding action. v

Then this material is carded in any approved manner, and itbecomes'extremelysoft and fiufiy, closly resembling cotton in very lightcondition, with its fibers in heterogeneous arrangement or Qdisposition.

As has been indicated, this material without being carded has severalsatisfactory uses, such as for pads beneath-carpets and rugs, forblotters, etc., and after undergoing the carding operation, it has manyuses, such as employment in the production of nitro-ce'llulose productssuch as explosives, a base for varnish, etc.; and. after being cardedand felted, as hereinafter explained, it has many other uses, such asfor hospital absorbent pads, sanitarypads, etc.

Such extremely light-and fiuffy, carded, cottony material is felted orcondensed in a continuous strip of suitable dimensions, such feltinginterlocking the variously arranged pulp-fibers, giving the product asatisfactory degree of strength.

Thereupon, a surface of the strip of cottonlike material is sprayed witha mixture of potato or corn starch, tapioca, dextrine ,or gelatin, orthe like, and alum or other water-repellent chemical, the'ratios ofthese two ingredients depending in large measure upon the use to IIwhich the finished product is to be put; but,'for

example, when it is to be used for sanitary napkins, the mixture may beninety nine (99%) per cent. starch and one (1%) per cent. alum.

Then two of these strips are placed together 20 with their starch-coatedfaces in contact, and these surfaces adhere together by reason of thedrying of such coatings, whereupon the continuousduplex strip is severedinto individual pads of, appropriate size. 7 '5 In the product, theintermediate layer of starch-treated pulp acts to bind the wholepadtogether and to give it adequate .strength throughout. I

The oil in the,pad,,,whose distribution and 80 action therein. has beenaided, and facilitated by the presence of the phenol, reduces orlocalizes the-.pads extremely absorbent properties suificiently so thatit may be employed advantageously,-and the oil causes a localization of.SI the absorbed liquid in the body of the pad, rather than to permit itto spread unduly at the surface. It will be understood that the oil maybe added after the felt has been formed instead of'prior to itsformation as in the case described.

This desirable action is increased and aided by the; intermediatestarch-and-alum treated stratum, which tends to retain rather thandisperse any liquid reaching it, and does not permit such liquid to beabsorbed directly andimmediately through the whole thickness of thepadat that point, and hence the absorptive qualities of theinterior ofthe pad are used 'to best advantage and without undue spreading of ,theliquid at any surface. I y This middle layer acts onlyas a deterrent inthis connection, and not as a complete prevention or bar, because it, isdesired-to use more or less of the whole absorbent qualities of the pad..Stated somewhat differently, the oil in the pad .5 and thestarch-and-alum layer act conjointiy, as y will bereadily understood, tocause aninterior slightly" less than that of water, which causes.

the material, after a few moments of saturation, to rise to the top ofthe water in a-conta'iner, and, therefore, when it is desired to disposeof agu'sed body of this material, it can be easily gotten rid of in thetoilet, because it is readily flushed through the usual: trapinterposed' u the pipin Where an absorbent pad is made of sheeted orstratified layers, they adhere together more or less, and henceseriously retard or hinder the required disintegration when it is to bedisposed of.

In some cases, it may be desirable to incorporate in the product amaterial of longer fiber than that of the "pulp itself forstr'engtheningpurposes, and accordingly in some instances cotton or other vegetablefiber may be mixed with 10 the wood-pulp, either before or after thecarding operation.

' Although in this patent I have referred more specifically towood-pulp, it is to be understood that the process is susceptible ofsatisfactory and beneficial employment with other more or less analogousvegetable materials, and even though the term wood-pulp be used in thefollowin claims, it may be construed broadly enough to cover equivalentmaterials. v

In the manufacture of cotton batting, wadding, etc., the glaze or finishprovided bythe binding starch is applied to one or more exte-. riorsurfaces of. the product, which is used in that condition, rather thanassociated with another-like portion of the'product, to make anintermediate or middlelayer of this character.

It is to be understood that the invention is not restricted or limitedto the precise ingredients specified, because all of these and otherfactors entering into the process may be modified within substantiallimits'without departure from the invention and the advantages whichaccrue from its employment, and one or moreof the ingredients specifiedmay be, omitted in some instances. 3

I claim:

1. The process of treating wood-pulp or similar material, consisting intreating the woodpulp with an oleaginous material having the property oflocalizing liquid absorption thereby, 40 carding-the pulp; felting thecarded pulp, and forming a stratum within the felted pulp adapted toretard the penetration of liquid from oneside. of the felt to the otherside of the felt and insure more complete distribution of said liquidthroughout the pad. I

2. The process of treating wood-pulp or similar material, conmsting inadding to the woodof liquid from one side of thefelt to the other sideof the-felt and insure more-complete dise tribution of said liquidthroughout the pad.

3. The process of treatingwood-pulp or'similar material, consistingdn.disintegrating the wood-pulp in water, reducing the volume of wateruntil five-(5%) per cent. of its weight is the disintegrated pulp,adding to each gallon of such liquid approximately one (1). gram of asolutioncomposed of about one thousand (1000) cubic centimeters ofrape-seed oil, approximately one (1) gram of crystallized phenol andabout one (1) gram of glycerin, agitating the mixture to cause thepulpto be thoroughly subjected to the solution, drawing off suchsolution and adding to each gallon thereof about one (1) gram ofbicarbonate of sodium and approximatelyhalf A a gram of potassiumhydrogen tartrate, sheeting the pulp; and drying-the pulp unde heat.

4. The, process of treating wood-pulp or similar material, consistingln-disintegrating the wood-pulp in water, reducing the volume of wateruntil five per cent. of its weight is the disintegrated pulp, adding toeach gallon of such liquid approximately one (1) gram of a solutioncomposed of about one thousand (1000) cubic centimeters of rape-seedoil, approximately one (1) gram of crystallized phenol and about one (1)gram of glycerin, agitating the mixture to cause the pulp to bethoroughly subjected to the solution, drawing off such solution andadding to each gallon thereof about one (1) gram of bicarbonate ofsodium and approximately half a gram of potassium-hydrogen tartrate,sheeting the pulp, drying the pulp under heat, and carding the driedpulp.

5. The process of treating wood-pulp or similar material, consisting indisintegrating the wood-pulp in water, adding rape-seed oil, phenol andglycerin thereto, then adding bicarbonate of sodium andpotassium-hydrogen tartrate thereto, then sheeting and drying the pulp,and then carding the dried pulp.

6. The process of treating wood-pulp or similar material consisting indisintegrating the dried pulp in water, adding in the same batch of pulpin water, chemicals which interact to form a leavening gas, and thendrying the pulp.

'7. The process of treating wood-pulp or similar material consisting indisintegrating the dried pulp in water, adding in the same batch of pulpin water, chemicals which upon heating liberate carbon dioxide gas, andthen drying the pulp.

8. The process of treating wood-pulp or similar material consisting indisintegrating the dried pulp in water, adding in the same batch of pulpin water, a salt of carbonic acid and an acid tartrate salt, and thendrying the pulp.

9. The process herein described which consists in disintegrating woodpulp in water, forming the disintegrated pulp into a continuous sheet,ab-

stracting water from the material of .said sheet and drying the same toconstitute a relatively soft sheet, with the fibres thereof relativelyloosely united to each other, carding such sheet, condensing the cardedmaterial to form a continuous strip of felted material and severing thestrip into individual pads.

10. The process herein described which consists in forming wood pulpinto a sheet with the individual fibres thereof relatively looselyunited to each other, carding such sheet, condensing such cardedmaterial to form a continuous strip of felted material, applying aqueousstarch to a surface of the material, uniting the starch coated face ofthe strip with a second strip of the felted material, so that saidstrips are caused to adhere by reason of drying of said coating andsevering the continuous duplex strip into individual pads.

11. The process herein described which consists in carding a sheet ofwood pulp having the individual fibres thereof relatively loosely unitedto each other, condensing such carded materials to form a continuousstrip of felted material, applying aqueous starch to a surface of thematerial, uniting the starch coated face of the strip with a secondstrip of the felted material, so that said strips are caused to adhereby reason of drying of said coating and severing the continuous duplexstrip into individual pads.

12. The process herein described which consists in carding a sheet ofwood pulp having the individual fibres thereof relatively loosely unitedto each other, condensing such carded material to form a strip of feltedwood pulp and associating with said wood pulp a vegetable material oflonger fibre than said wood pulp to strengthen the resultant product.

HARRISON R. WILLIAMS.

